If he speaks a word of kufr...
If he speaks a word of kufr, without knowing its meaning, or uses it in some other lawful meaning, then it would not be held against him. If he knew that it was a word of kufr and used it in the same meaning, he would become murtadd and najis, even if he was not aware of the consequences of his utterance. He should utter a word of kufr by his own free will. If he was forced to say such words and he did so to save his life (i.e. in taqiyyah), then it would not be held against him.
B) Apostasy may occur through heart, tongue and/or action:- ? Apostasy through heart: If someone disbelieves after believing or harbours doubt after being sure. ? Apostasy through tongue: When he denies the existence or oneness of Allah, or refutes God's justice or knowledge etc., or tries to show that God's actions are aimless or against Wisdom, or rejects any of the Zaruriyat-e-deen like prayer, fast, zakah, hajj, or disparages religion, qiyamat, Qur'an or hadith. ?
Apostasy through action: When someone, say, throws the Qur'an down (with intention of insulting it), or with that intention tears it down, or kicks at it or throws it into a dirty place. The same is the rule if he insults the books of du'a, or hadith, or the names of Allah C) There are three things which, without any difference of opinion, make a person kafir: Denial of any one of the Zaruriyat-e-Deen. Some of its examples have been given above. Objecting to any command of Allah.
It was this offence because of which Satan became kafir; otherwise he believed in one God, Qiyamat and almost all divine commands; but he objected to one order given by Allah and became kafir and accursed. The objection was: Why did you order me to do sajdah before Adam while I am superior to him? To treat any divine order with disdain even if it is a sunnah law. For example it is sunnah that moustache should be trimmed; now if someone disdainfully says: What nonsense is this?
Or, what it has got to do with shari'ah? He will become kafir: Now we come to the categories of apostates and their punishments :- Murtadd is of two kinds: Murtadd fitri and Murtadd Milli. Murtadd Fitri: A person both (or at least one) of whose parents were Muslims at the time of his conception, and then he/she, on attaining majority, renounces Islam by his own free will. The rules about Murtadd Fitri differ according to the sex of the offender, i.e.
there are different rules for males and females. A male murtadd fitri is to be killed.